Actuator

ABSTRACT

In the case of an actuator having a rotation angle sensor with a magnet, no satisfying solution has yet been found for the attachment of the magnet. The invention relates to an actuator having a rotation angle sensor, the magnet of the rotation angle sensor being provided with a plastic cover. The plastic cover and magnet may be easily connected to a first sensor part of the rotation angle sensor of the actuator. The actuator with the rotation angle sensor can particularly be used in motor vehicles.

PRIOR ART

The invention is based on an actuator as defined in the preamble to claim 1, a rotation angle sensor as defined in the preamble to claim 12, and a method for manufacturing an actuator as defined in the preamble to claim 13.

In a known actuator (DE 195 25 510 A1), a rotation angle sensor is provided for sensing an angular position of a rotor. Depending on the angular position of the rotor, a gas conduit extending through the housing of the actuator is opened to a greater or lesser degree by means of a throttle element connected to the rotor. In the known actuator, a first sensor part is situated on a gear connected to the rotor and a second sensor part is situated on a cover that is attached to the housing in a stationary fashion. In the actuator disclosed in DE 195 25 510 A1,the rotation angle is measured by means of moving sliders. It is, however, also possible to attach a magnet to the rotor, for example, and to attach a magnetically sensitive element to the stator. Depending on the position of the magnet of the rotor, the magnetic field acting on the magnetically sensitive element changes so that the magnetically sensitive element emits a corresponding electrical signal in accordance with the position of the rotor. Previously, the problem was the lack of a satisfactory solution for attaching the magnet to the rotor. For example, attaching the magnet to the rotor by means of screws would involve highly complex work. Casting the magnet into the plastic material of the rotor is also complex and requires a specific adaptation to different customer wishes and a significantly higher degree of complexity in the manufacture of the rotor. It is also possible to provide a deformable edge on the rotor, which is used by first placing the magnet against the rotor and then deforming the deformable edge so that the deformable edge encompasses part of the magnet, thus securing the magnet to the rotor. However, this has the disadvantage that the material normally used for the rotor, for example plastic, springs back slightly after the plastic deformation, thus resulting in play between the rotor and the magnet. As a result, the magnet can wobble somewhat in relation to the rotor. Another danger is that the deformation can change the properties of the plastic material of the rotor so that with the occurrence of temperature changes during operation of the actuator, the plastic material relaxes and as a result, the firm fit of the magnet is no longer assured. This leads to a distortion of the rotation angle sensor signal.

DISCLOSURE OF THE INVENTION Advantages of the Invention

The actuator according to the invention, with the defining characteristics of claim 1, the rotation angle sensor with the defining characteristics of claim 12, and the method for manufacturing an actuator with the defining characteristics of claim 13 have the advantage that the magnet embedded in the plastic casing can be attached very easily to the first sensor part. This connection can be produced by means of simple, proven, easy-to-implement, and very controllable manufacturing processes. The plastic casing accommodating the magnet can be very easily attached to the first sensor part, for example by means of ultrasonic welding, rotation welding, friction welding, gluing, etc.

Another advantage is that the magnet with the plastic casing can be manufactured as a blank on a mass production scale independently of the actuator, and then the mass-produced blank can be attached to various actuators. This has the advantage that in the event of a change to the actuator, no change to the actual rotation angle sensor is required.

Another advantage is that the magnet can be attached to the first sensor part without a high level of complexity by means of a method known to be reliable. A fastening method can be used in which it is known with certainty that no play between the rotor and the magnet will be produced even with the occurrence of temperature changes.

Advantageous modifications and improvements of the actuator and sensor are possible by means of the measures taken in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferably selected, particularly advantageous exemplary embodiments of the invention are shown in simplified fashion in the drawings and will be explained in detail in the subsequent description.

FIG. 1 shows a first exemplary embodiment,

FIG. 2 shows a detail at a different scale, and

FIG. 3 shows another exemplary embodiment.

EMBODIMENTS OF THE INVENTION

FIG. 1 shows an actuator 2 equipped with a rotation angle sensor 4. The rotation angle sensor 4 includes a first sensor part 6 and a second sensor part 8. In the exemplary embodiment shown, the first sensor part 6 is part of a rotatably supported rotor 10. The second sensor part 8 is part of a stator 12. In the exemplary embodiment shown, the rotor 10 essentially includes a throttle element shaft 14, a throttle element 16 fastened to the throttle element shaft 14 for co-rotation, and a rotation element 18 fastened to it for co-rotation. The stator 12 essentially includes a throttle element housing 20 with a gas conduit 22, which extends through the throttle element housing 20, and a housing cover 24.

The actuator 2 has an actuator motor 26 for producing an actuation force and a transmission for transmitting the actuating force from the actuator motor 26 to the rotation element 18 of the rotor 10. The actuating force is transmitted from the actuator motor 26 to the rotor 10 in the form of torques.

A detail of the actuator 2 shown in FIG. 1 is depicted in FIG. 2 at an enlarged scale and in a sectional view along the rotation axis of the rotor 10. The plane of the section shown in FIG. 2 is marked with II-II in FIG. 1.

In all of the figures, parts that are the same or function in the same manner have been provided with the same reference numerals. Provided that nothing to the contrary is mentioned or shown in the drawing, that which is mentioned and depicted in connection with one of the figures also applies to the other exemplary embodiments.

The first sensor part 6 includes a blank 30. The blank 30 is essentially composed of the magnet 32 and a plastic casing 34.

The magnet 32 is positioned a slight distance apart from the second sensor part 8. The magnet 32 has a side 32 a oriented toward the second sensor part 8. Toward the side 32 a, the magnet 32 has one indentation 32 b or several indentations 32 b along its circumference.

The blank 30 including the magnet 32 and the plastic casing 34 can be manufactured separately on a machine especially provided for this purpose. The blank 30 is manufactured by inserting the magnet 32 into an injection mold and then injection-molding a plastic material around it. In the process of this, the plastic material travels into the indentation 32 b provided in the magnet 32. This produces an intimate, fatigue-resistant, in particular co-rotating connection between the magnet 32 and the plastic casing 34. The blank 30 can be manufactured so that there is no plastic material on the side 32 a oriented toward the second sensor part 8 but instead, the magnet 32 extends to the surface of the blank 30 on the side 32 a. This achieves the smallest possible distance between the magnet 32 and the second sensor part 8.

A fastening point 36 a is provided on the plastic casing 34 of the blank 30. By means of the fastening point 36 a, a connection 36 is produced between the blank 30 and the rotation element 18 of the rotor 10. In the exemplary embodiment shown, the fastening point 36 a is a circumferential end surface oriented toward the rotation element 18. The fastening point 36 a of the blank 30 can, for example, be attached to the rotation element 18 by means of glue, ultrasonic welding, laser welding, friction welding, or another known fastening method. An integrally joined, form-locked, or nonpositive, frictional connection 36 can be provided.

The second sensor part 8 on the stator 12 includes a magnetically sensitive element 38. The magnetically sensitive element 38 can be used to sense the strength of a magnetic field and/or the direction of a magnetic field. The element 38 emits an electrical signal as a function of the magnetic field acting on the magnetically sensitive element 38 and/or as a function of the direction of the magnetic field. The rotation angle sensor 4 can thus be used to measure the relative rotation angle position between the first sensor part 6 and the second sensor part 8.

The proposal is made to manufacture the blank 30 so that in lieu of a finished magnet, an as yet unmagnetized material suitable for producing a permanent magnet is provided with the plastic casing 34. Only after the blank 30 has been attached to the rotation element 18 by means of the fastening point 36 a and after all of the material-removing machining of the actuator 2 has been completed is the magnetizable material constituting the magnet 32 permanently magnetized by means of a powerful external magnetic field applied to the side 32 a.

FIG. 3 shows another exemplary embodiment of an actuator embodied according to the invention.

Provided that nothing to the contrary is mentioned or shown in the drawings, the details of the various exemplary embodiments can be combined with one another.

In the exemplary embodiment of an actuator 2 shown in FIG. 3, which is embodied in the form of a gas pedal, the rotation element 18 is connected to a lever 40. By pressing on the lever 40, a driver of a vehicle can produce an actuating force. The actuating force moves the two sensor parts 6, 8 in relation to each other. By means of the lever 40, the driver can move the rotation element 18 and therefore the first sensor part 6 from an unactuated position into an actuated position. A return spring action 40 likewise acting on the rotation element 18 provides a continuous return force for moving the rotation element 18 into the unactuated position. In the exemplary embodiment shown, the second sensor part 8 provided on the stator 12 constitutes a pedal housing.

The actuator 2 with the two sensor parts 6, 8 that are movable in relation to each other can be embodied in different ways. The actuator 2 can, for example, be a throttle valve assembly, an electrically adjustable regulating valve, or an actuator in an air-conditioning system, or the actuator 2 can be embodied so that it can be used to control a heat distribution in an internal combustion engine, as a wiper drive unit, as a power window unit, as a power seat adjustment unit, etc.

In the preferably selected exemplary embodiments shown, the second sensor part 8 with the magnetically sensitive element 38 is situated on the stator 12 and the first sensor part 6 with the blank 30 is situated on the rotor 10. This can, however, also be reversed. Depending on suitability of the routing of electrical lines to the magnetically sensitive element 38, it can be advantageous to provide the magnetically sensitive element 38 either on the stator 12 or on the rotor 10. 

1-13. (canceled)
 14. An actuator with a rotation angle sensor, comprising: a first sensor part equipped with a magnet; a second sensor part equipped with a magnetically sensitive element, the first sensor part and the second sensor part being rotatable in relation to each other by means of an actuating force; and a plastic casing injection-molded at least partially around the magnet, wherein the plastic casing is connected to the first sensor part
 15. The actuator as recited in claim 14, wherein the plastic casing is at least partially open on at least one side.
 16. The actuator as recited in claim 14, wherein the plastic casing is closed on all sides.
 17. The actuator as recited in claim 14, wherein together with the plastic casing, the magnet constitutes a separately manufacturable blank.
 18. The actuator as recited in claim 15, wherein together with the plastic easing, the magnet constitutes a separately manufacturable blank.
 19. The actuator as recited in claim 16, wherein together with the plastic casing, the magnet constitutes a separately manufacturable blank.
 20. The actuator as recited in claim 14, wherein the plastic casing is connected to the first sensor part by means of an integrally joined connection.
 21. The actuator as recited in claim 18, wherein the plastic casing is connected to the first sensor part by means of an integrally joined connection.
 22. The actuator as recited in claim 19, wherein the plastic casing is connected to the first sensor part by means of an integrally joined connection.
 23. The actuator as recited in claim 14, wherein the plastic casing is connected to the first sensor part by means of a form-locked connection.
 24. The actuator as recited in claim 18, wherein the plastic casing is connected to the first sensor part by means of a form-locked connection.
 25. The actuator as recited in claim 19, wherein the plastic casing is connected to the first sensor part by means of a form-locked connection.
 26. The actuator as recited in claim 20, wherein the plastic casing is connected to the first sensor part by means of a nonpositive, frictional connection.
 27. The actuator as recited in claim 23, wherein the plastic casing is connected to the first sensor part by means of a nonpositive, frictional connection.
 28. The actuator as recited in claim 14, wherein the first sensor part is associated with a rotor and the second sensor part is associated with a stator.
 29. The actuator as recited in claim 14, wherein the first sensor part is associated with a stator and the second sensor part is associated with a rotor.
 30. The actuator as recited in claim 14, wherein the first sensor part is connected for co-rotation to a throttle element that controls a flow of a fluid.
 31. The actuator as recited in claim 14, wherein it is possible to rotate the first sensor part by means of a manually actuatable lever.
 32. A rotation angle sensor having a first sensor part equipped with a magnet and having a second sensor part equipped with a magnetically sensitive element, in which the two sensor parts are rotatable in relation to each other by means of an actuating force, the magnet having a plastic casing injection-molded at least partially around it, wherein the plastic casing is connected to the first sensor part.
 33. A method for manufacturing an actuator having a first sensor part equipped with a magnet and having a second sensor part equipped with a magnetically sensitive element, comprising a first method step in which a blank containing the magnet is manufactured by injection-molding a plastic casing at least partially around the magnet and a subsequent method step in which the plastic casing of the blank is attached to the first sensor part for co-rotation. 